sort ingress by namespace and name when ingress.CreationTimestamp identical

[nic-6443]

What this PR does / why we need it:
Because store.ListIngresses() sort Ingresses using the CreationTimestamp field and s.listers.IngressWithAnnotation.List() use map as backend cache , So when the list contains more than one Ingress with the same creationTimestamp, the sorting results are unstable.

// ListIngresses returns the list of Ingresses
func (s *k8sStore) ListIngresses(filter IngressFilterFunc) []*ingress.Ingress {
	for _, item := range s.listers.IngressWithAnnotation.List() {
                //Irrelevant logic ignored
		ingresses = append(ingresses, ing)
	}

	// sort Ingresses using the CreationTimestamp field
	sort.SliceStable(ingresses, func(i, j int) bool {
		ir := ingresses[i].CreationTimestamp
		jr := ingresses[j].CreationTimestamp
		return ir.Before(&jr)
	})

	return ingresses
}

For the reasons mentioned above, the output of Server.rootLocation logic will be equally unstable, resulting in slight differences in nginx.conf generated each time, triggering repeated meaningless nginx reload.
Server.rootLocation generate in controller.createServers()

for _, ing := range data {
         anns := ing.ParsedAnnotations
	for _, rule := range ing.Spec.Rules {
		if _, ok := servers[host]; ok {
			// server already configured
			continue
		}
		loc := &ingress.Location{
			Path:         rootLocation,
			IsDefBackend: true
		}

                //Because of the unstable order, anns may point to  different ingress.annotaions
		locationApplyAnnotations(loc, anns) 

		servers[host] = &ingress.Server{
			Locations: []*ingress.Location{
				loc,
			}
		}
	}
}

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

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[k8s-ci-robot]

Hi @ProNic-QY. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[aledbf]

@ProNic-QY please don't assign PRs manually

[aledbf]

Also, please sign the CLA

[nic-6443]

I signed it

[aledbf]

/ok-to-test

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@443886e). Click here to learn what that means.
The diff coverage is 33.33%.

@@            Coverage Diff            @@
##             master    #4409   +/-   ##
=========================================
  Coverage          ?   59.78%           
=========================================
  Files             ?       89           
  Lines             ?     7020           
  Branches          ?        0           
=========================================
  Hits              ?     4197           
  Misses            ?     2389           
  Partials          ?      434

Impacted Files	Coverage Δ
internal/ingress/controller/store/store.go	61.64% <33.33%> (ø)

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[ElvinEfendi]

/lgtm

[aledbf]

/hold

[nic-6443]

@aledbf Why remove this PR from 0.26.0?

[aledbf]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, ElvinEfendi, ProNic-QY

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• OWNERS [ElvinEfendi,aledbf]

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